Vehicle tow bar and tow ball protection devices are known. A very good discussion of the prior art devices is given in U.S. Pat. No. 6,412,806 and is reproduced below:
“Protective coverings for trailer hitches have been known for quite some time. U.S. Pat. No. 2,671,675 to Swaisgood (1950) discloses such a device. The Swaisgood device is particularly adapted to the type of hitches found in its era—which were typically mounted right next to the vehicle bumper. It does provide protection against accidental contact with the grease and grime on the hitch ball. It also creates an attractive appearance for the covered hitch. However, the Swaisgood device is quite cumbersome to remove and install. It requires the use of a wrench on an exposed bolt head. Additionally, because it is a hard-surfaced device, it does not prevent injury to persons accidentally walking into the hitch.
A device more adapted to modern hitch construction is disclosed in U.S. Pat. No. 4,955,968 to Beckerer, Jr. (1990). The Beckerer, Jr., device is formed as a single piece of molded plastic or rubber. In the case of the plastic version, it has a stand-off distance from the metal of the hitch, thereby providing some cushion for things striking the hitch. The molded rubber version, being apparently made of closed-cell foam (see FIG. 11 of '968 disclosure) appears to provide even more injury protection. The Beckerer, Jr., device appears to adequately protect the area of the hitch ball itself. However, modern hitch assemblies have extendable draw bars which may protrude 18 inches or more beyond the vehicle's bumper. The '968 device provides no protection for all that additional metal, which can certainly cause injury as well.
U.S. Pat. No. Des. 316,069 to Yocum (1991) discloses an ornamental design similar to the '968 disclosure. Like the '968 disclosure, it only covers the area immediately surrounding the hitch ball. A similar configuration is disclosed in U.S. Pat. No. Des. 317,745 to Beckerer, Jr. (1991).
U.S. Pat. No. 5,037,122 (1991) to Beckerer, Jr., discloses a refinement of the '968 device. The '122 disclosure provides an improved version of the closed-cell foam rubber protector. It also discloses improved techniques for engaging the device with the hitch assembly. However, the reader will also note that the '122 device is still limited to the area immediately surrounding the hitch ball. Those skilled in the art will also realize that many of the variations disclosed would be difficult to install and remove.
A modern extended draw bar type hitch is disclosed in U.S. Pat. No. 5,421,601 to Hinze et. al. (1995). FIG. 1 of the Hinze et. al. nicely illustrates the shortcoming of a guard which only covers the area immediately adjacent to the hitch ball. A great deal of potentially dangerous metal is left exposed. The Hinze et. al. device addresses this concern with a large, bifurcated box. The box is hollow and split into two halves. Each half can be slipped around the bulky hitch assembly, and then locked together using the clips shown. Because the box is rigid, it must be greatly oversized to accommodate the many variations in hitch assemblies. Those skilled in the art will realize that the hitch assembly illustrated can be adjusted substantially in several directions. This fact causes problems for the approach taken in Hinze et. al.
The known devices for protecting a trailer hitch assembly are therefore limited in that they:    1. Require tools to install and remove;    2. Are difficult to install and remove;    3. Only protect the area immediately surrounding the hitch ball;    4. Are too bulky; and    5. Are not sufficiently flexible to accommodate variations in hitches.”
These problems remain even with the solution proposed in U.S. Pat. No. 6,412,806.
It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.